The present invention relates to an image analyzing apparatus and, particularly, to such an apparatus for quantitatively analyzing an image included in a region of interest.
Various image analyzing methods are known. These include an autoradiographic process comprising the steps of introducing a radioactively labeled substance into an organism, using the organism or a part of the tissue of the organism as a specimen, placing the specimen and a radiographic film such as a high sensitivity type X-ray film together in layers for a certain period of time to expose the radiographic film thereto and obtaining locational information regarding the radioactively labeled substance in the specimen from the resolved pattern of the radiographic film, a chemiluminescent process comprising the steps of selectively labeling a fixed high molecular substance such as a protein or a nucleic acid sequence with a labeling substance which generates chemiluminescent emission when it contacts a chemiluminescent substance, contacting the high molecular substance selectively labeled with the labeling substance and the chemiluminescent substance, detecting the chemiluminescent emission in the wavelength of visible light generated by the contact of the chemiluminescent substance and the labeling substance and obtaining information relating to the high molecular substance such as genetic information, a detecting method using an electron microscope comprising the steps of irradiating a metal or nonmetal specimen with an electron beam, detecting a diffraction image, transmission image or the like and effecting elemental analysis, composition analysis of the specimen, structural analysis of the specimen or the like, or irradiating the tissue of an organism with an electron beam and detecting an image of the tissue of the organism, and a radiographic diffraction image detecting process comprising the steps of irradiating a specimen with radiation, detecting a radiographic diffraction image and effecting structural analysis of the specimen or the like.
Conventionally, these methods are carried out by employing a photographic film as a detecting material, recording a radiographic image, a chemiluminescent image, an electron microscopic image, a radiographic diffraction image or the like on the photographic film and observing a visual image with the eyes. However, in the case where a photographic film is employed as a detecting material, since a radiographic film has low sensitivity, there is a problem that it takes considerable time for recording an image in the autoradiographic process and the radiographic diffraction image detecting process. Further, in the chemiluminescent process, although it is necessary to employ a highly sensitive film having a high gamma value for detecting very weak chemiluminescent emission, when the highly sensitive film having a high gamma value is employed, it is difficult to expose the film reliably using a straight portion of the characteristic curve. Therefore, the film is often exposed improperly and it is necessary to repeatedly expose the films under various exposure conditions. Moreover, in the detecting process using the electron microscope, since the straight portion of the characteristic curve of a photographic film for an electron microscope is short, it is difficult to determine the proper exposure condition and it is necessary to repeatedly expose the films. Furthermore, in either processes, it is indispensable to chemically develop the films and, therefore, the operations are unavoidably complicated.
In view of the above, there have been proposed an autoradiographic process, a chemiluminescent process, a detecting process using an electron microscope and a radiographic diffraction image detecting process comprising the steps of employing, as a detecting material for the radiation, the visible light, the electron beam or the like, not a photographic film, but a stimulable phosphor which can absorb and store the energy of radiation, visible light, an electron beam or the like upon being irradiated therewith and release a stimulated emission whose amount is proportional to that of the received radiation, the visible light, the electron beam or the like upon being stimulated with an electromagnetic wave having a specific wavelength range, photoelectrically detecting the stimulated emission released from the stimulable phosphor, converting the detection signal to a digital signal, effecting a predetermined image processing on the obtained image data and reproducing an image on displaying means such as a CRT or the like or a photographic film (See for example, Japanese Patent Publication No. 1-60784, Japanese Patent Publication No. 1-60782, Japanese Patent Publication No. 4-3952, U.S. Pat. No. 5,028,793, UK Patent Application 2,246,197 A, Japanese Patent Application Laid Open No. 61-51738, Japanese Patent Application Laid Open No. 61-93538, Japanese Patent Application Laid Open No. 59-15843 and the like).
According to the detecting processes using the stimulable phosphor, development, which is a chemical processing, becomes unnecessary. In addition, the exposure time can be markedly shortened in the autoradiographic process and the radiographic diffraction image detecting process. Improper exposure becomes rare and the exposing operation becomes easy in the chemiluminescent process and the detecting process using the electron microscope. Further, since the image is reproduced after the detected signal has been converted to a digital signal, the image can be reproduced in a desired manner by effecting signal processing on image data and it is also possible to effect quantitative analysis using a computer. Use of a stimulable phosphor in these process is therefore advantageous.
An image forming/analyzing apparatus for effecting an autoradiographic process, a chemiluminescent process, a detecting process using an electron microscope or a radiographic diffraction image detecting process using stimulable phosphor sheets should preferably be able to define a desired region in image data as a region of interest, evaluate amounts of light emitted from a stimulable phosphor sheet as the density of the pixels constituting an image included in the region of interest, obtain the sum thereof, conduct quantitative processing, group a plurality of regions of interest, calculate the density ratio between the pixels in the regions of interest belonging to any particular group and conduct quantitatively analysis.
For instance, in the thin layer chromatography widely used in research into drug metabolism, for analysis of how a drug labeled with a labeling substance and introduced into a test animal changes in the body of the animal is conducted by collecting specimens of urine, blood, tissue or the like from a specific region of the animal at predetermined time intervals, processing the specimens in a predetermined manner and dropping the processed specimens at predetermined positions at regular intervals on a TLC plate which is formed by coating a glass plate with powders of silica gel. The TLC plate is dipped in a distribution solvent and the specimens are chromatographically distributed, thereby forming separate spots for individual components of the specimens. It is often necessary, based on image data obtained by placing the thus produced TLC plate onto a stimulable phosphor sheet, to define regions corresponding to certain spots as regions of interest, group a plurality of predetermined regions, evaluate the density of each region and obtain ratios between the densities of respective regions belonging to the group.
The image forming/analyzing apparatus for effecting such quantitative processing and analysis normally includes graphic data storing means for storing graphic data such as coordinate data of patterns surrounded by a circle, a rectangle or a broken line used for defining a region of interest. This graphic data storing means is provided independently of image data storing means for storing image data. FIG. 11 is a functional block diagram showing the configuration of a conventional graphic data storing means. As shown in FIG. 11, graphic data storing means 200 stores a graphic database 201 and a quantitative database 202. The graphic database 201 includes pattern number data 203 indicating the pattern numbers, pattern type data 204 indicating pattern types such as circle pattern or rectangular pattern and coordinate data 205 indicating pattern positions on an image. The quantitative database 202 includes density data 206 indicating the signal levels of image data contained in a region defined by patterns, region data 207 indicating pattern areas and group data 208 indicating groups to which patterns belong.
When an operator draws a pattern on the screen of a display means (not shown) using a mouse (not shown), graphic data 210 consisting of the pattern number data 203, the pattern type data 204 and the coordinate data 205 are stored in the graphic database 201. The operator then further operates the mouse in a predetermined manner for calculating the area of the pattern and density data 206 corresponding to the signal levels of the image data enclosed by the region defined by the pattern. The results are stored in the graphic data storing means. Moreover, the group data 208 indicating the group to which the pattern belongs are stored in the graphic data storing means by operating the mouse in a predetermined manner.
Further, for enabling the density data to be more accurately calculated, it is necessary to remove from the density data corresponding to background noise, namely noise components uniformly recorded on the stimulable phosphor sheet by cosmic rays, ground radiation or inherent radiation contained in, for example, the TLC plate onto which the specimens are chromatographically distributed. Therefore, the image forming/analyzing apparatus is constituted so that a pattern can be drawn at a region whose density is to be zero on an image displayed on the display means as a background pattern, that a reference background value, namely, density per unit area, can be calculated based on the density of the pattern and that the density data can be more accurately calculated based on the reference background value. For this purpose, the quantitative data base 202 further includes background number data 209 indicating the pattern numbers produced as background patterns.
The thus produced graphic data 210 are synthesized with image data stored in the image data storing means to be output to display means such as a CRT and the synthesized data are displayed on the screen of the display means. The density of the pixels constituting an image contained in a region defined by a pattern belonging to a particular group, accurate density obtained by removing the background density from the density of the pixels, density ratios between patterns belonging to a certain group or the like are displayed.
However, since only one background pattern is allotted per group in the conventional image forming/analyzing apparatus, a background pattern cannot be determined for each pattern belonging to a group so that an accurate reference background value cannot be obtained for each pattern. In particular, in the case where a plurality of substances are chromatographically distributed by dropping them on different TLC plates whose materials and inherent radiation amounts are different from each other and the distributed substances are transferred onto a stimulable phosphor sheet to obtain image data, if a plurality of patterns defining regions corresponding to spots formed on the different TLC plates are allotted to one group, it is impossible to determine an accurate background value for each of the patterns and to accurately calculate the density of the region defined by each of the patterns.
Further, since each pattern displayed on the display means belongs to only one group, the conventional image forming/analyzing apparatus has the following problem.
Consider, for instance, the case described above in which images obtained by simultaneously dropping a plurality of substances on a TLC plate and chromatographically distributing them thereon are recorded on a stimulable phosphor sheet, thereby obtaining image data, whereafter regions corresponding to positions on the TLC plate where spots are formed are defined as regions of interest and a plurality of regions among these regions are grouped. In this case, if regions corresponding to a plurality of spots contained in an image pattern of one substance are grouped to one group, these regions cannot belong to any group including regions corresponding to spots contained in an image pattern of other substances.
Therefore, for instance, in the case where drugs are introduced to a test animal and tissue of a particular part thereof is collected at predetermined time intervals to be chromatographically distributed, it is impossible to simultaneously obtain an amount ratio between components of the tissue collected at one time and an amount ratio between corresponding components of the tissues collected at a different time and in the case where drugs are introduced into a plurality of test animals and tissues of a particular part thereof are collected to be chromatographically distributed, it is impossible to simultaneously obtain an amount ratio between components of the tissue collected from one test animal and an amount ratio between corresponding components of the tissues collected from a different test animal. Therefore, the images in the regions of interest that were defined by patterns cannot smoothly be analyzed.
The same problems occur in the case where, after recording an autoradiographic image, a chemiluminescent image, an electron microscopic image, a radiographic diffraction image or the like on a photographic film, the recorded image is photoelectrically read and converted to a digital signal and the thus obtained image signal is signal processed in a desired manner, thereby reproducing a visible image on displaying means such as a CRT or a photographic film.
It is therefore an object of the present invention to provide an image analyzing apparatus which can accurately and smoothly qualitatively process and analyze an image contained in a region of interest defined by a pattern.
The above and other objects of the present invention can be accomplished by an image analyzing apparatus comprising image data storing means for storing image data, display means for displaying an image based on image data selected from the image data stored in the image data storing means and processed in a predetermined manner, graphic data storing means for storing graphic data corresponding to a plurality of patterns to be displayed on the display means, quantitative processing means for quantitatively processing image data corresponding to the images contained in regions of interest defined by the patterns, quantitative data storing means for storing quantitative data produced by the quantitative processing means, and background management means for producing and storing background data relating to background values corresponding to noise components for each of the regions of interest.
In a preferred aspect of the present invention, an image analyzing apparatus further comprises background value producing means for producing the background values based on the background data stored in the background management means and the quantitative data stored in the quantitative data storing means and table data producing means for producing table data including the background value for each of the regions of interest and the display means is adapted to display a table based on the table data.
In a further preferred aspect of the present invention, the graphic data storing means is adapted to store pattern numbers allotted to the patterns defining the regions of interest and the background management means comprises background storing means for storing a pattern number of the pattern defining the region of interest to be processed using the background value.
In a further preferred aspect of the present invention, the background management means is constituted so as to select graphic data corresponding to at least one pattern from the graphic data stored in the graphic data storing means and produce the background data based thereon to produce the background value.
In a further preferred aspect of the present invention, the background management means is adapted to allot a background number to the at least one pattern and the background storing means is adapted to store the pattern numbers in a region of the corresponding background number.
In a further preferred aspect of the present invention, the background value producing means is adapted to produce density data of pixels constituting an image defined by the pattern and area data representing an area of the image and a reference background value per unit area based thereon, thereby producing the background value.
In a further preferred aspect of the present invention, in the case where the background value is produced using a plurality of patterns, the background value producing means is adapted to determine the reference background value by averaging the reference background values of the plurality of patterns.
The above and other objects of the present invention can be also accomplished by an image analyzing apparatus comprising image data storing means for storing image data, display means for displaying an image based on image data selected from the image data stored in the image data storing means and processed in a predetermined manner, graphic data storing means for storing graphic data corresponding to a plurality of patterns to be displayed on the display means, quantitative processing means for quantitatively processing image data corresponding to the images contained in regions of interest defined by the patterns, quantitative data storing means for storing quantitative data produced by the quantitative processing means, and group data storing means for storing group data determined for showing the relationship between the patterns and groups to which the patterns belong.
In a preferred aspect of the present invention, an image analyzing apparatus further comprises table data producing means for producing table data including a ratio of quantitative data for each of the groups based on the group data stored in the group data storing means and quantitative data stored in the quantitative data storing means and the display means is adapted to display a table based on the table data.
In a further preferred aspect of the present invention, the graphic data storing means is adapted to store pattern number data allotted to the patterns defining the regions of interest and coordinate data showing positions of the patterns in the image data and the group data storing means is adapted to store the pattern number data of the patterns belonging to each of the groups.
In a further preferred aspect of the present invention, the table data producing means is adapted to produce table data for each of the groups and the display means is adapted to display a table based on the table data so that data are displayed for each of the pattern number data.
In a further preferred aspect of the present invention, the quantitative data produced by the quantitative data producing means comprise density data of pixels constituting images contained in regions of interest defined by the patterns and area data indicating areas of the regions defined by the patterns.
In a further preferred aspect of the present invention, the image data are produced using a stimulable phosphor sheet.
In a further preferred aspect of the present invention, the image data are constituted by image data selected from a group consisting of autoradiographic image data, radiographic diffraction image data, electron microscopic image data and chemiluminescent image data.
In a further preferred aspect of the present invention, the autoradiographic image data, the radiographic diffraction image data and the electron microscopic image data are produced by absorbing and storing the energy of a radiation or an electron beam emitted from a specimen in a stimulable phosphor, irradiating the stimulable phosphor with an electromagnetic wave and photoelectrically converting light emitted from the stimulable phosphor.
In a further preferred aspect of the present invention, the chemiluminescent image data are produced by absorbing and storing the energy of a visible light emitted from a specimen in a stimulable phosphor, irradiating the stimulable phosphor with an electromagnetic wave and photoelectrically converting light emitted from the stimulable phosphor.
In the present invention, the stimulable phosphor employed for producing an autoradiographic image, a radiographic diffraction image and an electron microscopic image may be of any type insofar as it can store radiation energy or electron beam energy and can be stimulated by an electro-magnetic wave to release the radiation energy or electron beam energy stored therein in the form of light. However, a stimulable phosphor which can be stimulated by light having a visible light wavelength is preferably employed. More specifically, preferably employed stimulable phosphors include alkaline earth metal fluorohalide phosphors (Ba1xe2x88x92x,M2+x)FX:yA (where M2+ is at least one alkaline earth metal selected from the group consisting of Mg, Ca, Sr, Zn and Cd; X is at least one halogen selected from the group consisting of Cl, Br and I, A is at least one element selected from the group consisting of Eu, Tb, Ce, Tm, Dy, Pr, He, Nd, Yb and Er; x is equal to or greater than 0 and equal to or less than 0.6 and y is equal to or greater than 0 and equal to or less than 0.2.) disclosed in U.S. Pat. No. 4,239,968, alkaline earth metal fluorohalide phosphors SrFX:Z (where X is at least one halogen selected from the group consisting of Cl, Br and I; and Z is at least one of Eu and Ce.) disclosed in Japanese Patent Application Laid Open No. 2-276997, europium activated complex halide phosphors BaFXxc2x7xNaXxe2x80x2:aEu2+ (where each of X or Xxe2x80x2 is at least one halogen selected from the group consisting of Cl, Br and I; x is greater than 0 and equal to or less than 2; and y is greater than 0 and equal to or less than 0.2.) disclosed in Japanese Patent Application Laid Open No. 589-56479, cerium activated trivalent metal oxyhalide phosphors MOX:xCe (where M is at least one trivalent metal selected from the group consisting of Pr, Nd, Pm, Sm, Eu, Tb, Dy, Ho, Er, Tm, Yb and Bi; X is at least one halogen selected from the group consisting of Br and I; and x is greater than 0 and less than 0.1.) disclosed in Japanese Patent Application Laid Open No. 58-69281, cerium activated rare earth oxyhalide phosphors LnOX:xCe (where Ln is at least one rare earth element selected from the group consisting of Y, La, Gd and Lu; X is at least one halogen selected from the group consisting of Cl, Br, and I; and x is greater than 0 and equal to or less than 0.1.) disclosed in U.S. Pat. No. 4,539,137 and europium activated complex halide phosphors MIIFXxc2x7aMIXxe2x80x2xc2x7bMxe2x80x2IIXxe2x80x32xc2x7cMIIIXxe2x80x2xe2x80x33xc2x7xA:yEu2+ (where MII is at least one alkaline earth metal selected from the group consisting of Ba, Sr and Ca; MI is at least one alkaline metal selected from the group consisting of Li, Na, K, Rb and Cs; Mxe2x80x2II is at least one divalent metal selected from the group consisting of Be and Mg; MIII is at least one trivalent metal selected from the group consisting of Al, Ga, In and Tl; A is at least one metal oxide; X is at least one halogen selected from the group consisting of Cl, Br and I; each of Xxe2x80x2, Xxe2x80x3 and Xxe2x80x2xe2x80x3 is at least one halogen selected from the group consisting of F, Cl, Br and I; a is equal to or greater than 0 and equal to or less than 2; b is equal to or greater than 0 and equal to or less than 10xe2x88x922; c is equal to or greater than 0 and equal to or less than 10xe2x88x922; a+b+c is equal to or greater than 10xe2x88x922; x is greater than 0 and equal to or less than 0.5; and y is greater than 0 and equal to or less than 0.2.) disclosed in U.S. Pat. No. 4,962,047.
In the present invention, the stimulable phosphor employed for producing a chemiluminescent image may be of any type insofar as it can store the energy of light having a visible light wavelength and can be stimulated by an electromagnetic wave to release the energy of light having a visible light wavelength stored therein in the form of light. However, a stimulable phosphor which can be stimulated by light having a visible light wavelength is preferably employed. More specifically, preferably employed stimulable phosphors include metal halophosphates, rare-earth-activated phosphors, aluminate-host phosphors, silicate-host phosphors and fluoride-host phosphors disclosed in UK Patent Application 2,246,197 A.
The above and other objects and features of the present invention will become apparent from the following description made with reference to the accompanying drawings.